So, as other companies have done with varying results in the past, it is looking around for some kind of relief. One option is to see if anybody's taking advantage of you behind your back.

It made one such important decision on March 12, when it filed a lawsuit against social networking giant Facebook over 10 patents that include methods and systems for advertising on the Web, the first major legal battle among big technology companies in social media. No dollar amounts were mentioned.

Yahoo had threatened this move back on Feb. 28. It now has pulled the trigger. The Sunnyvale, Calif.-based Web services company said it is seeking licensing fees from Facebook over its patents and that other companies have already agreed to such licensing deals.

In the lawsuit, Yahoo says Facebook was considered "one of the worst performing sites for advertising" prior to adapting Yahoo's ideas. "Mr. Mark Zuckerberg, Facebook's founder and CEO, has conceded that the design of Facebook is not novel and is based on the ideas of others," the lawsuit said.

In a statement to Reuters, Yahoo said it is confident it will prevail. "Unfortunately, the matter with Facebook remains unresolved and we are compelled to seek redress in federal court."

Legal Move Comes Six Weeks After Facebook IPO News

Yahoo's announcement comes in the wake of Facebook's plans for an initial public offering that could value the company at about $100 billion. Hmmm.

Facebook spokesman Jonathan Thaw told Reuters that his company learned of the lawsuit through the media. "We're disappointed that Yahoo, a longtime business partner of Facebook and a company that has substantially benefited from its association with Facebook, has decided to resort to litigation," he said in a statement.

Yahoo has retained the same law firm, Quinn Emanuel Urquhart & Sullivan, used by Google and other manufacturers in several Android-related smartphone patent cases.

Curiously, Quinn Emanuel also has social gaming service Zynga as a client. Zynga is a close partner of Facebook, bringing in about 12 percent of Facebook's revenue, according to Facebook's IPO statement of Feb. 1.

The lawsuit, filed in federal court in San Jose, is the latest legal event in a major influx of patent litigation that has hit the smartphone and tablet sectors and high-visibility companies such as Apple, Microsoft and Motorola Mobility Holdings.